5. Junkers J-13 (F-13)
Little more than a decade after the Wrights first flew, Hugo Junkers reinvented the airplane. Historian Charles Gibbs-Smith writes of Junkers: “He may be fully and fairly credited with the design and construction of the first practical cantilever [internally braced] wing aeroplanes, the first practical all-metal aeroplanes, and the first low-wing monoplanes.” Junkers adopted the thick wing, which produced greater lift and enabled construction of cantilever wings. Suspicious of wooden construction, he opted for metal. Junkers’ transformational airplane was the J-13 of 1919, which, in mass production, was better known as the F-13. It had a low wing, an enclosed cabin, an all-metal structure, and a high degree of streamlining, and launched both global air transport and the era of the mass-produced, all-metal, aluminum-alloy airplane. More than 300 were delivered around the world, and it spawned a series of similar-looking descendants, culminating in 1932 in the Junkers Ju 52. By 1924, Junkers supplied fully 40 percent of the world’s transports, placing Germany at the forefront of air transport design, a position it held until dethroned by the United States in the early 1930s.
C. Gibbs-Smith, The Aeroplane: An Historical Survey (HMSO, 1960);
R. Blunck, Hugo Junkers: Ein Leben für Technik und Luftfahrt (Econ-Verlag GmbH, 1951 edition);
Hans-Liudger Dienel and Martin Schiefelbusch, “German Commercial Air Transport Until 1945,” in Revue belge de philologie et d’histoire, vol. 78, no. 3-4 (2000).
6. Zeppelin-Staaken (Rohrbach) E.4/20
Adolf Rohrbach narrowly missed being Germany’s Boeing or Douglas, largely because of the fate of his E.4/20. Like Junkers, Rohrbach favored thick-wing cantilever monoplanes, but unlike Junkers, who used tubes and ribs covered with corrugated sheet, Rohrbach used dural stressed skin employing a single torsion-box spar running from wingtip to wingtip, its smooth top and bottom serving as the wing’s upper and lower surfaces. Leading- and trailing-edge ribs, attached to the front and back faces of this box and covered with thin dural sheet, gave the wing its shape. His E.4/20 of 1920 was a streamlined, all-dural design powered by four engines, weighing 18,700 pounds loaded. Only large wheels and landing gear struts marred its lines, and its high-placed, tapered, cantilever wing spanned 102 feet. It had a cabin that seated up to 18, as well as a lavatory and generous mail and luggage space. At its first flight, in 1920, both its design and performance—cruising more than 130 mph at less than full power, and ranging nearly 850 miles—were a good dozen years beyond what any other airliner had attained.
To comply with post-World War I restrictions, the Allies ordered it destroyed in November 1922, a sad loss. But though never itself produced, many of its features—stressed skin, torsion-box spar, leading edge engines, and gracefully tapered wing—became standard elements of long-range aircraft, as did its general configuration.
A. K. Rohrbach, “Das 1000-PS Verkehrsflugzeug der Zeppelin-Werke, Staaken,” Zeitschrift für Flugtechnik und Motorluftschiffahrt, vol. 12, no. 1 (15 Jan. 1921); E. Offermann, W. G. Noack, and A. R. Weyl, Riesenflugzeuge, a volume in the Handbuch der Flugzeugkunde series (Richard Carl Schmidt & Co., 1927).
7. Bäumer Sausewind
Paul Bäumer was a master of reinvention: a pre-war dental assistant turned wartime fighter ace, a postwar dentist, and then an airplane manufacturer. His streamlined, two-place Sausewind (“Rushing Wind”), designed to compete in a 1925 light-aircraft race, anticipated the definitive streamlined form of the propeller-driven airplane. Designed by Walter Gunter, who, together with his brother Siegfried, possessed a rare genius, the airplane had a beautiful wooden elliptical wing joined to a smooth, plywood monocoque fuselage, with similar elliptical vertical and horizontal tail surfaces. Bäumer died in a 1927 accident flying another company’s airplane, and the Gunters moved to Heinkel. There, they used the Sausewind's aerodynamic shape for the Heinkel He 70 Blitz high-speed transport. Beverly Shenstone, who worked with Reginald Mitchell at Vickers Supermarine and was responsible for the Spitfire’s aerodynamic design, recalled that he “used the He 70 as an aerodynamic target when calculating the Spitfire performance,” praising its “brilliance and style.” It was the ultimate compliment one could pay the Sausewind, which flew with a perfect elliptical wing a full decade before Mitchell’s legendary fighter.
Georg Madelung, “Der Otto Lilienthal Wettbewerb,” in Wilhelm Hoff (editor), Jahrbuch 1926 der Deutschen Versuchsanstalt für Luftfahrt, e.v., Berlin-Adlershof (DVL, 1926);
Richard von Mises, “Mathematical Problems in Aviation,” The American Mathematical Monthly, vol. 47, no. 10 (Dec. 1940);
H. Dieter Köhler, Ernst Heinkel—Pionier der Schnellflugzeuge (Bernard & Graefe, 1999);
B.S. Shenstone, “Germany’s Turbulent Pioneer,” The Aeroplane (7 Feb. 1958).